Grinding apparatus

ABSTRACT

THIS INVENTTION RELATES TO IMPROVEMENTS IN GRINDING APPARATUS, AND MORE PARTICULARLY CONCERNS A METHOD AND APPARATUS FOR WET GRINDING THE EDGES OF A PANE OR SHEET OF GLASS. THE APPARATUS INCLUDES A GRINDING WHEEL, COOLANT FEED MEANS FOR FEEDING A COOLANT TO THE GRINDING WHEEL, A HOOD ENCLOSING THE GRINDING WHEEL AND HAVING A SLOT FOR RECEIVING THE EDGE OF THE GLASS SHEET, AND MEANS FOR DRAWING AIR AROUND, OVER, AND BENEATH THE SHEET OF GLASS IN SUCH A MANNER THAT SUBSTANTIALLY ALL OF THE COOLANT IS PREVENTED FROM LEAVING THE HOOD WITH THE GLASS SHEET. THE METHOD INCLUDES FEEDING A COOLANT TO A GRINDING WHEEL ENCLOSED IN A HOOD, CONTACTING THE GRINDING WHEEL WITH THE EDGE OF THE GLASS SHEET, AND DRAWING AIR AROUND, OVER, AND BENEATH THE GLASS SHEET IN SUCH A MANNER THAT SUBSTANTIALLY ALL OF THE COOLANT IS PREVENTED FROM LEAVING THE HOOD.

Jan. 12, 1971 v. A. HORDIS 3,553,910

' GRINDING APPARATUS Filed March 6, 1967 I I 4 Sheets-Sheet 1 INVENTOR F I I VICTOR HORDIS ATTORNEY av I K. F7

Jan. 12 1971 v HORDIS 3,553,910

GRINDING APPARATUS Filed March 6, 1967 4 Sheets-Sheet 2 HNVENTOR VICTOR A. HORDIS ATTORNEY 4 Sheets-Sheet s V. A. HORDIS GRINDING APPARATUS INVENTOR ATTORNEY VICTOR A. HORDIS F I G. 3.

Jan. 12, 1971 Filed Marc zh e, 1967 Jan. 12, 1971 v. A. HORDIS GRINDING APPARATUS Filed March 6, 1967 V 4 Sheets-Sheet 4 -INVENTOR VICTOR A. HORDIS ATTORNEY United States Patent O 3,553,910 GRINDING APPARATUS Victor A. Hordis, Riverton, N.J., assignor, by mesne assignments, to Hordis Bros., Inc., Pcnnsauken, N.J., a corporation of Pennsylvania Continuation-impart of application Ser. No. 540,632, Apr. 6, 1966. This application Mar. 6, 1967, Ser. No. 621,048

Int. Cl. B24b 55/02, 55/04 US. Cl. 51-356 7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to improvements in grinding apparatus, and more particularly concerns a method and apparatus for wet grinding the edges of a pane or sheet of glass.

The apparatus includes a grinding wheel, coolant feed means for feeding a coolant to the grinding wheel, a hood enclosing the grinding wheel and having a slot for receiving the edge of the glass sheet, and means for drawing air around, over, and beneath the sheet of glass in such a manner that substantially all of the coolant is prevented from leaving the hood with the glass sheet.

The method includes feeding a coolant to a grinding wheel enclosed in a hood, contacting the grinding wheel with the edge of the glass sheet, and drawing air around, over, and beneath the glass sheet in such a manner that substantially all of the coolant is prevented from leaving the hood.

CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part of my co-pending patent application Ser. No. 540,632, filed Apr. 6-, 1966, now abandoned.

BACKGROUND OF THE INVENTION Within the past ten years, the glass industry has started to use and has rapidly converted to high-speed machines for grinding the edges of glass sheets or panes. These highspeed machines utilize diamond grinding wheels which remove glass very rapidly, but must be operated wet. However, because of the high speed of rotation of their grinding edges (from six to ten thousand feet per minute), these wheels tend to throw ofif their coolant, which may be water, very rapidly. This raises a problem, since these wheels must be wet at all times while grinding in order to dissipate the high heat generated by the grinding operation, prolong the life of the grinding wheels, and maintain the speed of grinding and give the desired finish of the ground glass. Fast heat dissipation is often necessary in order to prevent any edge cracking of the glass.

Under these conditions of operation, to keep the grinding wheels adequately supplied with a sufficient amount of coolant, it has been necessary, prior to this invention, to supply the grinding wheel with a very large flow of coolant. Disposing of this large coolant flow raises another problem.

Additionally, it has been a problem to restrain the coolant from leaving the grinding area too quickly, and to reduce as much as possible the coolant splash in and around the machine. Prior devices have been inadequate, in that the glass is flooded with coolant, and this makes handling the glass very messy. Moreover, the coolant contained ground glass and had to be washed from the glass sheet to remove all dirt, and ground glass. The carryover of coolant and ground glass into washing machines causes trouble in the washing machines because the ground glass Works through its mechanism and raises a serious and costly maintenance problem.

The coolant in prior devices also flooded much of the grinding machine so that all parts of the grinding machine had to be cleaned regularly to remove ground glass, thus adding to the maintenance cost of the grinding machine and causing premature failure of many of its components.

Another problem with prior grinding devices is that they generated an unhealthy mist of coolant and ground glass that surrounded the grinding machine and extended outwardly therefrom to cover an area of 10 to 12 feet in diameter. This mist could lead to the developing of silicosis by the people operating these machines for an extended period of time.

SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provlde grinding apparatus for grinding the edges of a sheet of glass which overcomes the foregoing problems and disadvantages of the prior art.

It is another object to substantially eliminate coolant splash and the problems in maintenance and machine design caused by such splash.

It is another object to provide for effective grinding with a reduced coolant flow.

It is another object to provide grinding apparatus WhlCh includes means for controlling coolant splash during the process of edge grinding glass.

It is another object of this invention to substantially reduce the health hazard to the employees engaged in glass grinding using todays high-speed equipment.

The objects of the invention are accomplished by provlding a hooded grinding Wheel, feeding a coolant to the grinding wheel, and drawing the coolant away from the glass sheet and preventing it from flowing out over the sheet or misting into the atmosphere.

BRIEF DESCRIPTION OF THE DRAWINGS ment of grinding apparatus constructed in accordance with the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS Turning now to the specific embodiment of the invention selected for illustration in FIGS. 1-3 of the drawings, there is shown apparatus for wet-grinding the edges of a pane or sheet 11 of glass which comprises a grinding wheel 13, a hood 15 enclosing grinding wheel 13 and having a slot 17 formed therein for receiving glass pane 11 so that its edge may contact the grinding edge of wheel 13, coolant feed means for feeding a coolant 19, which may be water, to the grinding wheel, and vacuum means for drawing the coolant 19 and preventing it from flowing out over the pane 11.

It is another object of this invention to provide grinding apparatus wherein the machine parts can be more precisely designed by eliminating the contamination from ground glass particles which penetrated the parts of previous apparatus and by eliminating the design allowance and dimensional tolerances made for such contamination.

It is another object to eliminate the objectionable working conditions currently involved in the high-speed wetgrinding of glass. It is an object to eliminate the necessity of the operators of the grinding apparatus having to wear aprons and gloves which soon became soggy from the coolant which ran over the sheet of glass when operating prior art devices.

It is another object to prolong the life and substantially reduce the maintenance of grinding apparatus, while at the same time allowing the refinement of designing components for high-speed glass grinding equipment.

Grinding wheel 13 is mounted on a spindle which extends from a motor 21 and is positioned so that it rotates in a horizontal plane. Slot 17 is parallel to the plane of grinding wheel 13 and includes a front slot 23 in the front of hood 15, and side slots 25 which are formed in the sides of the hood.

A coolant tank 27 is positioned below hood 15, and the coolant feed means includes a pump 29 positioned in the tank 27, and a coolant feed pipe 31 which extends from the pump 29 and terminates in a coolant outlet 33 that is positioned in close proximity to grinding wheel 13. Outlet 33 directs the coolant 19 substantially tangentially to the periphery of wheel 13, and the wheel rotates in a direction away from coolant outlet 33. Accordingly, the periphery of wheel 13 picks up coolant 19 before contacting the edge of pane 11 and then the wheel throws off the coolant 19 after it has contacted the pane edge.

The vacuum means which draws off the coolant and prevents it from runnig over the pane includes a fan 35 which has an exhaust opening 37, a suction pipe 39 connecting hood to fan 35 for exhausting the coolant from the hood, and a drain pipe 41 connecting the suction pipe 39 to the coolant tank 27 for returning the used coolant 19 to the tank.

In operation, the edge of pane 11 is inserted into slot 17 which acts as a glass and air entrance. The coolant 19 is directed substantially tangentially to the grinding edge of wheel 13 which picks up the coolant on its surface. The grinding edge of the wheel 13 contacts the edge of the pane 11 and grinds it to the desired finish. The coolant 19 dissipates the heat during this grinding operation and then is carried by the rotation of the wheel to a point past the grinding area and is thrown into the interior of hood 15. The vacuum caused by fan 35 draws air into hood 15 through slot 17. This air flow prevents any coolant 19 or mist created by the grinding operation from leaving the hood 15 through the glass entry slot 17, and also prevents the coolant 19 from flowing out over the large fiat surfaces of the glass pane.

Also, the rush of air into slot 17 holds the coolant 19 against the grinding wheel 13 so that a much smaller volume of coolant flow is needed. The spent coolant 19,

along with the air drawn into hood 15, is drawn into suction pipe 39, and the spent coolant separates from the air at the entrance to drain pipe 41 and flows down through drain pipe 41 into coolant tank 27 by gravity. From coolant tank 27, the coolant 19 is eventually reumped to grinding wheel 13 during the course of this continuous operation.

The lower end of drain pipe 41 is positioned below coolant level 43 so as to maintain the vacuum, or negative pressure, in hood 15 and suction pipe 39. The fan 35 develops about nine inches of water suction, so that the level 45 of coolant in drain pipe '41 is about nine inches above coolant level 43. The air in suction pipe 39 passes through fan 35, the negative pressure developing device, and is discharge-d to the atmosphere through exhaust opening 37. If desired, this air may be discharged through exhaust opening 37 through a filter to remove any entrapped mist. However, no mist has been observed going through exhaust opening 37 One of the advantages accruing to grinding apparatus using this invention is that the machine parts can now be more precisely designed since no allowance has to be made for contamination from ground glass particles which penetrate the parts of previous apparatus and cause a major cleaning and maintenance problem.

Another advantage of the invention is that it provides a solution to the major problem of handling the coolant so as to eliminate coolant splash. Previously, the operators of the grinding apparatus had to wear aprons and gloves which soon became soggy from the coolant which ran over the pane or sheet of glass. The new invention makes the use of such protective aprons and gloves unnecessary, and thus provides for better working conditions.

The embodiment of the invention illustrated in FIGS. l3 of the drawings shows the use of an external centrifugal fan. It will be realized that other means of providing the suction may be used, such as mounting a fan impeller on the grinding wheel itself or on the grinding wheel spindle so that the source of power for the grinding wheel would also provide power to operate the suction producing means.

Turning now to the specific embodiment of the invention shown in FIG. 4, there is shown apparatus for wet grinding edges of a pane or sheet of glass 51 which comprises a grinding wheel 53 that is mounted on a spindle 55 driven by a motor 57.

Grinding wheel 53 is enclosed by a hood 59 that is provided with a front entrance slot 61 and side entrance slots 63 that receive the glass sheet so that its edge may contact grinding wheel 53 and be ground thereby.

Coolant feed means are provided for feeding a coolant 65, which may be water, to grinding wheel 53, and a vacuum means is provided for drawing the coolant 65 away from the surfaces of the sheet of glass 51 so as to prevent the coolant from spreading over the pane of glass.

The coolant feed means includes a coolant tank 67 positioned below grinding wheel 53 and connected to hood 59 by a housing 69 which forms a chamber in which is mounted a pump 71. An inlet pipe 73 connects the coolant 65 in tank 67 to pump 71, and a coolant feed tube 75 extends from pump 71 to the periphery of grinding wheel 53 and directs the coolant onto the wheel in a tangential fashion. Pump 71 is driven by a shaft 77 which is in turn driven through a belt 79 by a shaft 81 extending upwardly from motor 57.

The vacuum means includes a fan impeller 83 mounted on shaft 81 of motor 57. Impeller 83 draws air from slots 61 and 63 through hood 59 and housing 69, and through a chamber 85 formed by a housing 87 between motor 57 and fan housing 89.

Fan impeller 83 also draws air through openings 91 in the bottom of motor 57 upwardly through the motor to cool the motor, and then through chamber 85 into fan housing 89.

If desired, a filter may be positioned in the path of the coolant 65 being drawn from the sheet of glass 51 by the vacuum means. The filter may include a roll 93 of filter paper mounted above hood 59, with a continuous sheet 95 of filter paper extending downwardly across the hood through narrow slots 97, 98. The sheet 95 of filter paper is positioned in the path of the discharge air flowing from the grinding wheel and removes most of the ground glass therefrom.

When the coolant is not filtered, it contains bits of ground glass and diamond chips, and this coolant forms a grinding slurry that helps prevent the grinding wheel from glazing, and keeps the diamonds on the wheel open and standing out from their holding matrix and free to work efficiently until worn out. Accordingly, it is felt that this grinding slurry improves the performance and lengthens the life of the grinding wheel. All makes of grinding wheels may not be similarly affected. The method shown is one which can be used when it is desired to filter the coolant.

The air passing through fan impeller 83 may be discharged into the room through fan outlet 99. However, if desired, the discharge air may be returned through return conduit 101 to hood slots 61 and 63. This recirculation of the discharge air improves the efficiency of the vacuum system and reduces the power needed to operate the fan impeller. A damper 103 may be provided in the return conduit 101 in order to regulate the amount of discharge air returned to hood 59, and a door 104 may be provided to exhaust some of the air.

Spindle 55 is contained Within a spindle housing 105 that is mounted on the bottom of motor housing 57. Spindle housing extends into hood 59, and a slot 107 is provided between hood 59 and housing 105. The vacuum means draws air through slot 107 to keep the coolant away from the spindle. This prevents the diamond and glass chips of the coolant from reaching and damaging the spindle bearings.

The return air from conduit 101 is directed into the entrance slots 61 and 63 toward the grinding wheel to thereby convey the coolant in the direction away from the entrance slots and away from the sheet of glass. This blowing action therefore assists the suction means in preventing the coolant from spreading over the pane of glass.

The embodiment of the invention shown in FIG. 4 is a completely self-contained unit that is operated by a single motor and is completely enclosed. It incorporates an inexpensive filter system which may be used if desired, and also returns the discharge air to the inlet slots of the hood.

It is felt that wheel life is extended by the better coolant distribution to the working part of the wheel which is accomplished by the present invention. Some of the coolant thrown otf the wheel by centrifugal force whirls around inside the hood and is picked up by the entering air and washed along the flat surfaces of the glass pane into the grinding wheel.

The discharge air leaving the hood and entering the chamber formed by housing 69 is of reduced velocity so that the coolant drops out of the mixture of air and coolant and falls into coolant tank 67 before the air is sucked into the fan housing 89 by the fan impeller 83.

It is to be understood that the form of the invention herewith shown and described is to be taken as a presently preferred embodiment. Various changes may be made in the shape, size and arrangement of parts. For example, equivalent elements may be substituted for those illustrated and described herein, parts may be reversed, and certain features of the invention may be utilized independently of the use of other features, all without departing from the spirit or scope of the invention as defined in the subjoined claims.

I claim:

1. Apparatus for wet grinding edges of a pane of glass, comprising a grinding wheel, a hood enclosing the grinding wheel and having a slot for receiving the glass pane so that its edge may contact the grinding wheel, coolant feed means for feeding a coolant to the grinding wheel, and vacuum means for drawing the coolant and preventing it from flowing out over the pane of glass or misting into the surrounding air, including a coolant tank, and wherein said vacuum means includes a suction pipe extending from the hood to an exhaust opening for the air, a fan positioned in the suction pipe for drawing the coolant and air into the suction pipe, and a drain connected to the suction pipe and extending downwardly therefrom so that the used coolant may separate by gravity from the air and return to the tank, wherein said fan develops about 9 inches of coolant suction so that the level of coolant in the drain pipe is about 9 inches higher than the level of coolant in the coolant tank.

2. Apparatus for wet grinding edges of a pane of glass, comprising a grinding wheel, a hood enclosing the grinding wheel and having a slot for receiving the glass pane so that its edge may contact the grinding wheel, coolant feed means for feeding a coolant to the grinding wheel, and vacuum means for drawing the coolant and preventing it from flowing out over the pane of glass or misting into the surrounding air, including a coolant tank, said coolant feed means including a pump positioned in the coolant tank, and a coolant feed pipe extending from the pump and terminating in a coolant outlet positioned in close proximity to the grinding wheel, said grinding wheel being positioned so that it rotates in a horizontal plane, said slot being parallel to the plane of the grinding wheel and having a front slot in the front of the hood and side slots which are formed in the sides of the hood, said vacuum means including a suction pipe extending from the hood to an exhaust opening for the air, a fan positioned in the suction pipe for drawing the coolant and air into the suction pipe, and a drain connected to the suction pipe and extending downwardly therefrom so that the used coolant may separate by gravity from the air and return to the tank, wherein said fan develops about 9 inches of coolant suction so that the level of coolant in the drain pipe is about 9 inches higher than the level of coolant in the coolant tank.

3. Apparatus for wet grinding edges of a pane of glass including a grinding wheel, and Coolant feed means for feeding a coolant to the grinding wheel, wherein the improvement comprises a hood enclosing the grinding wheel and having a slot for receiving the glass pane so that its edge may contact the grinding wheel, and a vacuum means for drawing the coolant and preventing it from flowing out over the pane of glass or misting into the surrounding air, including a motor, a spindle connected between the motor and grinding wheel for rotating the wheel, said vacuum means including a fan connected to the motor and driven thereby, a coolant tank below the wheel, a housing connecting the hood to the fan and to the coolant tank, a pump, an inlet pipe connecting the coolant tank to the pump, a coolant feed tube extending from the pump to the grinding wheel whereby to direct coolant onto the wheel, and means connecting the motor to the pump for driving the pump.

4. An apparatus for wet grinding edges of a pane of glass including a grinding wheel, and coolant feed means for feeding a coolant to the grinding wheel, wherein the improvement comprises a hood enclosing the grinding wheel and having a slot for receiving the glass pane so that its edge may contact the grinding wheel, and a vacuum means for drawing the coolant and preventing it from fiovw'ng out over the pane of glass or misting into the surrounding air, including a motor, a spindle connected between the motor and grinding wheel for rotating the wheel, said vacuum means including a fan connected to the motor and driven thereby, a coolant tank below the wheel, a housing connecting the hood to the fan and to the coolant tank, a pump, an inlet pipe connecting the coolant tank to the pump, a coolant feed tube extending from the pump to the grinding wheel whereby to direct coolant onto the wheel, and means connecting the motor to the pump for driving the pump, wherein the fan is mounted on top ofthe motor with a housing therebetween so that the fan draws air upwardly through the motor from beneath for cooling the motor.

5. Apparatus for wet grinding edges of a pane of glass including a grinding wheel, and coolant feed means for feeding a coolant to the grinding wheel, wherein the improvement comprises a hood enclosing the grinding wheel and having a slot for receiving the glass pane so that its edge may contact the grinding wheel, and a vacuum means for drawing the coolant and preventing it from flowing out over the pane of glass or misting into the surrounding air, including a filter positioned in the path of the coolant being drawn from the glass pane by said vacuum means, said filter including a roll of filter material mounted above the hood, and a sheet of filter material extending from the roll across the hood.

6. Apparatus for wet grinding edges of a pane of glass including a grinding wheel, and coolant feed means for feeding a coolant to the grinding wheel, wherein the improvement comprises a hood enclosing the grinding wheel and having a restricted opening for receiving the glass pane so that its edge may contact the grinding wheel, a vacuum means for drawing the coolant away from the pane and restricted opening and preventing it from flowing out over the pane of glass or misting into the surrounding air, and a suction pipe connected to the hood, said suction pipe having a larger volume than the restricted opening so as to slow the velocity of the air passing therethrough to permit the gravity separation of the coolant carried by the air.

7. Apparatus for wet grinding edges of a pane of glass including a grinding wheel, and a coolant feed means for feeding a coolant to the grinding wheel, wherein the improvement comprises a hood enclosing the grinding wheel and having a restricted opening for receiving the glass pane so that its edge may contact the grinding wheel, and a vacuum means for drawing the coolant away from the pane and restricted opening and preventing it from flowing out over the pane of glass or misting into the surrounding air, said vacuum means drawing air from the hood and discharging it therefrom, and means for returning the discharged air to said restricted opening in the hood, said grinding wheel being rotated by a motordriven spindle in a spindle housing connected to the 8 hood, said hood being provided with a slot between hood and spindle housing, the vacuum means drawing air through said slot to keep the coolant away from the spindle.

5 References Cited UNITED STATES PATENTS 2,110,441 3/1938 Kasch 51-267 1,512,889 10/1924 Henry 51267X 10 2,742,974 4/1956 Landgraf 51-273X 3,321,871 5/1967 Balamuth et a1. 51273X FOREIGN PATENTS 897,214 11/1953 Germany 51--267 17,447 1914 Great Britain 51-273 JAMES L. JONES, JR., Primary Examiner 0 US. Cl. XJR. 

